1. Field of The Invention
This invention relates to a light emission diode which is capable of emitting light in a wavelength range of blue.
2. Description of The Prior Art
Among light emission diodes which are typical of potential light emitting parts, red light emission diodes using AlGaAs and green light emission diodes using GaP have been in wide use mainly as display devices. From the standpoint of multicoloration and upgrading of function, there is now a strong demand for blue light emission diodes whose luminous intensity is high. For the fabrication of such a blue light emission diode, it will be sufficient to use materials whose forbidden band width is great. In this sense, fabrication of blue light emission diodes has been hitherto proposed including ones which make use of SiC, GaN, and compounds of II-VI groups of the periodic table such as ZnSe, ZnS and the like. However, the diodes using any of these compounds are not satisfactory in practical use with respect to the luminous intensity. For instance, with the ZnS compound which is a compound semiconductor of the II-VI group, blue light emission is based on a deep level. However, the resultant diode involves much of non-luminous transition. Thus, the luminous intensity of the diode is so weak as not to suit for practical use.